The invention relates generally to motion control fluid devices and monitoring of fluid properties in motion control fluid devices.
Motion control fluid devices that are of interest here are those that are configured to be attached between two structures, such as aircraft rotary wing members, in order to control relative motion between the two structures. Such a motion control fluid device includes at least one chamber containing a fluid. The motion control fluid device may also include at least one elastomer bonded to two surfaces subjected to relative motion. The motion control fluid device generates a motion force, via controlled motion of the fluid within the at least one chamber (and constrained motion of the at least one elastomer, if present), when a disturbance, such as vibrations from an attached structure, is applied to the motion control fluid device. Depending on the configuration of the motion control fluid device, the motion control force may be used to damp down the applied disturbance or to isolate the applied disturbance. In some cases, the motion control fluid device may include a volume compensator to maintain a steady pressure within the device and thereby avoid abnormally high or low pressures within the device. The health of such devices can be assessed by monitoring fluid properties, such as pressure, in the devices.